Switch for electric conductors



(No Model.)

0'. OFFRELL. v SWITCH FOR ELECTRIC 001111110110113.

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OLOF OFFRELL, OF MIDDLETCWN, CONNECTICUT, ASSIGNOR TO THE SCI IUYLER ELECTRIC COMPANY, OF CONNECTICUT.

SWITCH FOR ELECTRIC CONDUCTORS.

SPECIFICATION forming part of Letters Patent No. 501,191, dated July 11, 1893.

Application filed August 12,1892- Serial No. 442,878. (No model.)

To all whom it may concern:

Be it known that I, OLOF OFFRELL, a sub ject of the King of Norway and Sweden,who have declared my intention of becoming a citizen of the United States, residing at Middletown, county of Middlesex, State of Connecticut, have invented certain new and useful Improvements in Switches 'for Electric Conductors, of which the following is a specification.

My invention relates to switches for closing and breaking electric circuits, and its object is to provide a cheap and efficient snap switch; that is, one in which the circuit is suddenly and forcibly opened and closed.

In the drawings, Figure 1 is a side elevation of my invention. Fig. 2 is a top plan view. Fig. 3 is a side elevation of the stem. Fig. 4 is a cross-section of the stem. Fig. 5 is a perspective view of one of the spring contact arms. Fig. 6 is a vertical section of the switch on the line a--b Fig. 2.

The base A is composed of any good electrical insulating substance, such as porcelain. Rising from its surface are two diametrically opposite blocks B, of insulating material, and preferably formed integral with the base A. Secured to the base adjacent to the ends of the blocks 13 are two contact pieces C of metal to which the line Wires are secured by screws a. The inner faces of the blocks and contact pieces are preferably flat and form a rectangular or other quadrilateral cavity. At one end of each block B is a lug b in which is cut a beveled notch 19 one edge of which coincides with the adjacent edge of the contact piece C; the notches being diametrically opposite. A stem F is rotatably mounted in a hole in the base A, so as to stand centrally in the cavity. It has a head or thumb-piece D by which it can be readily turned. A diametrical slotF is made in the stem, extending up to a point above the base A. In this slot are received the spring arms E, each arm being made separate, in the form shown in Fig. 5, having at one end a raised portion such as the transverse rib e and at a little distance from it a depression, such as the transverse groove (1, the space, between the groove and the rib being equal to the diameter of the stemvF. Two of these arms are put together, with the rib on each fitting into the corresponding groove on the other. Thus assembled they are slid into the slot in the stem,as shown in Fig. 4, the ribs and grooves preventing the arms from coming out of the slot. The stem is then inserted into its hole in the base, where it is secured bya washer b and the pin 0. The arms E are so much longer than the cavity in which they are received that they are compelled to assume a curved shape, running spirally from the stem to the sides of the cavity. This puts them under constant tension, so that they press tightly against the contact pieces C and make a good electrical connection therewith. Moreover, when the stem is turned so as to slide the arms off the contact pieces, the ends of the arms snap suddenly into the notches b breaking the circuit instantly. The curved shape of the arms prevents the stem from being turned backward, since the ends of the arms'abut against the blocks B when a backward motion is given to the stem.

What I claim as new, and desire to secure by Letters Patent, is

1. In an electric switch, a stem having a central slot, and contact arms consisting of two strips of metal, having their ends lapped and received in said slot, substantially as set forth.

2. In an electric switch, a stem having a central slot, and contact arms consisting of two strips of metal provided with interlocking portions, received in said slot, substantially as described.

3. The combination with a stem having a central slot, of two strips of metal, one having a raised portion and a depression fitted to a corresponding depression and raised portion on the other, said meeting portions of the strips being received in the slot in the stem, substantially as set forth.

4. The combination with a stem having a central slot, of two strips received in said slot each having a transverse rib and groove, fit- In witness whereof I have hereunto set my ted together and lying adjacent to the stem, hand. substantially as set forth.

5. A spring contact arm for an electric OLOF OFFRELL. 5 switch, consisting of the strip E having the Witnesses:

transverse groove d and rib e, substantially EDWARD R. KNOWLES,

GEO. R. WHI'ITLESEY.

as set forth. 

